Sheet drying machine



NOV. 17, 1931. c HETZEL 1,831,911

SHEET DRYING MACHINE Original Filed Sept. 24, 1926 2 Sheets-Sheet l V INVENTOR BY um M L ATTORNEYS Nov. 17,1931. c.E. HETZEL 7 1,831,911

" SHEET DRYING MACHINE 0 Original Filed Sept. 24, 1926 2 Sheets-Sheet fly. .3 5

F .7 i INVENTOR ATTORNEYS I Patented Nov. 17, 1931 UNITED STATES PATENT OFFICE CHARLES E. .HETZEL, OFjG-LE'NZBROOK, CONNECTICUT, ASSIGNOR TO ZELOID PRODUCTS CORPORATION, OF HOLYOKE, MASSACHUSETTS, A CORPORATION OF DELAWARE SHEET DRYING MACHINE Application filed September 24, 1926, Serial No.137,465. Renewed March 28, 1980.

My invention relates to continuous drying machines for the drying of sheet material, and particularly to machines adapted to the drying of such a material as a coagulated sheet formed from dissolved cellulose.

An object of my invention is to provide a dryin machine for the drying of a sheet of cellu osic product of the type obtained by solution of cellulose and the coating, coagulating, and purifying as described in my copending applications, Serial Nos. 137,462; 137,463; 137,464; all filed September 24, 1926.

In the operation of drying the finished sheet obtained from a solution of cellulose, difficulty has been experienced in the control of the material during the drying process, in order to obtain a sheet which is of satisfactory transparency, of proper strength, unbroken, and free from buckles and wrinkles. I have found that in order to obtain proper drying of the cellulosio sheet it must be maintained under tension during the entire operation of drying, and it is essential that the drying proceed while the sheet is in motion.

My invention provides means whereby a sheet of the wet cellulosic material, formed as described in my copending applications, is threaded, and drawn continuously, throu h a drying chamber under controlled conditions of temperature and humidity, and under suitable tension in both lengthwise and crosswise directions.

By this means I obtain a continuous sheet of dry cellulosic material having exceptional surface polish, exceptional strength, transparency, uniformity, and freedom from wrinkles.

Other objects and structural details of my invention will be apparent from the follow-' ing description when read in connection with the accompanying drawings, wherein:

Fig. 1 is a diagrammatic representation of an embodiment of my apparatus in side elevation;

Fig. 2 is a representation of the same enfbodiment of my apparatus in plan view;

Fig. 3 is a view of an embodiment of a carrying roll of my invention;

Fig. 4 is a view of a tension roll and un1- versal joint;

\ tension, may be varied by an ad shown in Figs. 1 and 2, I provide a drying chamber 1 within which is positioned the conveying and drying device. I provide a frame-work 2 adapted to carry the support ing and bearing members of my invention. I further provide a series of paired archshaped members 3 supported upon the framework 2. Between the pairs of arch-shaped members 3 I provide a plurality of drying rolls 4.

Referring to Fig. 3, each drying roll 4 consists of a polished metal cylinder 5 to which is attached a spindle 6 adapted to cooperate with bearings 7, which are mounted in the arched member 3. Between the bear ings 7 and the respective endsof the cylinder 5, I position a pair of sprocket wheels 8, adapted to cause rotation of the cylinders 5 by the movement of cooperating chains, shown at 15 and 16 in Fig. 2.

The rolls 4 are adapted to carry the sheet of cellulosic material upon their surfaces. At the ends of the arched members 3 I provide additional rolls 9 with sprocket wheels It may be partially controlled by a suitable spring 10, either increasing or reducing the efl'ect of its weight upon the tension of the sheet. It may be held in position by a framework 11. The spring pressure, and the sheet 'usting screw 12, and the sprockets 8 should e loosely attached to the roll portion 5, in order that the chain tension may not affect the sheet tenslon.

At the entrance end of the machine I provide additional rolls 13- for feeding the wet sheet to the drying rolls. I further provide, adjacent to the feeding rolls 13, a reel support 14 upon which the reeled wet sheet,

'after delivery from the treating vats, may

be mounted for unrolling to the drier.

I further provide a pair of link driving chains 15 and 16, positioned upon opposite sides of the machine, and engaging all of the sprockets upon the respective sides of the machine. The chains may conveniently be driven by a power supply connected to sprockets 17 at the outlet end of the machine.

By this means all of the rolls 4, 9, 13, 17 and 18 are driven at auniform, similar, speed.

In the construction of the rolls I have found it convenient to crown them in a manner similar to that in which pulleys forveniently consists of a 'demountable spindle 20, driven through a variable speed mechanism, which may conveniently be a pair of crown pulleys with a shifting belt as shown, and a convenient power supply.

Suitable drying means are provided in the drying chamber. This may consists of steam coils 19 positioned adjacent the rolls 4 as in dicated, (or, under certain conditions electric heaters may be used), or, alternatively, the drying may be done by a current of conditioned air, of carefully controlled temperature and humidity. I may, if desired, subdivide the drying chamber and supply the various sections with conditioned air independently, thereby obtaining better control of the rate of drying at successive stages of the process.

The chains 15 and 16 are provided with special links at frequent intervals, conveniently about 12 inches apart, which carry swinging socket members 21, as shown in Figs. .5 and 6. The socket members are adapted to engage a cross-bar 22 to which the end of the wet sheet may be attached. The cross-bar 22 with the attached end of the wet sheet is adapted to' be inserted into the sockets 21 and drawn by the chains through the machine from the entrance to the exit end, carrying the sheet with it, and thereby greatly simplifying the process of threading the sheet through the machine. This obviates the necessity of an operator entering the drying -chamber.

. I have shown in the drawings only a limited number of successive arched members 3. The actual number used is determined by the speed of traverse which the sheet of wet material will stand, and by the rate at which the sheet can be dried. I

In the operation of my device a reel of wet sheet from the coagulating and purifying baths, is positioned upon the reel spindle 14. The end of the sheet is drawn from the reel and attached to a cross-bar member 22, as

shown in Fig. 5. The cross-bar is then inhumidity at the various points in the chamber. The values of temperature and humidity are controlled to complete the drying in the time of passage through the machine, and the end of the dried sheet is delivered by the cross-bar 22 to 'the exit end of the machine. The cross-bar is then removed, the end of the -"sheet attached to the reel spindle 20-, and the sheet wound up as dry finished product.

The temperature of the chambers may be controlled by the valves 23 which control the heating units 19. The humidity of the chambers may be controlled by the openings 24 at the top of the chambers and the openings 25 in the lower portion of the side wall of the chambers. The openings 23 and 24 when open causes a circulation of airwhich enters through the door in the lower portion of the sidewall and leaves through the door in the top of the chamber. This circulation of air carries moisture from the chamber; if desired, a'supply of dry air or moist air may be connected to the opening in the lower portion of the side wall so as to facilitate the control of humidity in the chamber.

Suitable tension is provided at the inlet end of the machine to maintain the sheet under the necessary tension. This tension is equalized and maintained by the tension rolls 4 at the top of each arch of rolls. The sheet is thus readily maintained under tenison in a lengthwise direction. It is, however, necessary that it be maintained under tension in a crosswise direction as well. This crosswise tension is produced by the crowning of the rolls, the amount of sidewise tension being determined by the amount of crown. By this means suitable tension, both lengthwise and crosswise of the sheet, is maintained during the whole of the drying process, and the sheet is delivered in a smooth transparent condition. The tension in two directions is also found to produce a sheet of much higher physical strength.

By this means ,I am enabled to obtain a dry sheet of homogeneous cellulosic material, which is flat', transparent, and of supe- 'rior tensile strength.

While I have shown but one embodiment of my invention it is capable of various modifications therefrom without departing from the spirit thereof, and it is desired therefore that only such limitations shall be imposed thereon as are required by the prior art or indicated in the appended claims.

I claim as my invention: 7

1. A drying machine comprising a plurality of drying rolls, an arched support therefor, an enclosure therearound, and driving means simultaneously engaging with all of said rolls.

2. A drying machine comprising a plurality of drying rolls,'an arched support therefor, a tensioning roll yieldingly mounted upon said arched support, driving means simultaneously engaging with said drying rolls and said tensioning roll, and an enclosure therearound.

3. In a drying machine a plurality of drying rolls, a pair of driving chains cooperating therewith, and a cross-bar adapted to draw a sheet of material across said rolls, said chains comprising groups of links, and socket links therebetween, said socket link comprising an auxiliary swinging member and a spring actuated socket adapted to coop:

erate with an end of a cross-bar.

4. A drying machine comprising a drying chamber, a plurality of drying rolls therein, a pair of driving chains cooperating therewith, said chains consisting of a plurality of lengths pivotally secured together, socket lengths pivoted to certain of said lengths, and a crossbar member adapted to engage said socket lengths for drawing a sheet of material past said drying rolls.

5. A drying machine comprising a drying chamber, a plurality of drying rolls therein, a pair of driving-chains cooperating therewith, said chains consisting o a plurality of lengths piv'otally secured together, socket lengths pivbted to certain of said lengths, anda cross bar member adapted to engage said socket lengths for drawing a sheet of material past drying rolls, said cross bar having a slot thereon adapted .to receive said mate-' rial.

In witness whereof, I hereunto subscribe my signature. CHARLES E. HETZEL. 

